Note 1 - Summary of Significant Accounting Policies - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Inputs, Level 1 [Member]
Total Assets	$ 1,660	$ 849
Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member]
Investments	879
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member]
Investments
Fair Value, Inputs, Level 1 [Member] | Government-backed and Government-sponsored Enterprises' Debt Securities [Member]
Investments
Fair Value, Inputs, Level 1 [Member] | Money Market and Mutual Funds [Member]
Other Assets	781	849
Fair Value, Inputs, Level 2 [Member]
Total Assets	7,090	8,225
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]
Investments
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Investments	4,991	5,280
Fair Value, Inputs, Level 2 [Member] | Government-backed and Government-sponsored Enterprises' Debt Securities [Member]
Investments	2,099	2,945
Fair Value, Inputs, Level 2 [Member] | Money Market and Mutual Funds [Member]
Other Assets